Biodegradation Of Tetracycline Research Articles

Biodegradation of Tetracycline and Ciprofloxacin in Aerobic Composting Using Different Microbial Sources

Biodegradation of Tetracycline and Ciprofloxacin in Aerobic Composting Using Different Microbial Sources

Molecular mechanism underlying the degradation of tetracycline by Apiotrichum loubieri MFZ-16

Microbial degradation of tetracycline (TC) is promising owing to its high efficiency and low price; however, a thorough knowledge of its biotransformation is still lacking. In this study, we isolated a novel TC-degrading strain, Apiotrichum loubieri MFZ-16, from kennel soils. Response surface model analysis showed that MFZ-16 degraded TC by 97.93% at 34.54 ℃, pH 5.06%, and 12.93% inoculation. Liquid chromatography-mass spectrometry and principal component analyses revealed significant differences in metabolites between TC-salt media with and without MFZ-16. Furthermore, eight key intermediates of TC degradation were identified and their reaction processes were predicted. Transcriptome analysis revealed that MFZ-16 contained 137 functional genes involved in TC biodegradation. Three TC metabolic pathways, namely, the tyrosine, tryptophan, and D-glucose 1-phosphate metabolic pathways, were predicted, and the tyrosine and tryptophan metabolic pathways were predicted for the first time. These results suggest that A. loubieri strain MFZ-16 is an efficient and promising microbe for TC bioremediation. These findings would give a new insight into the mechanism of TC degradation.

Leveraging anaerobic biodegradation of tetracycline in anaerobic digestion systems with different operational modes

Antibiotics such as tetracycline in wastewater may cause the operation failure of anaerobic digestion systems. With two types of operational modes, continuous-flow reactors (CFRs) and sequencing batch reactors (SBRs) were operated with or without the addition of tetracycline to examine the influence of tetracycline on system performance, tetracycline removal, metabolic activity, and microbial communities. Tetracycline inhibited the removal of chemical oxygen demand (COD) by 23.9% in CFRs and 20.5% in SBRs, and led to the accumulation of volatile fatty acids (VFAs). Also, the maximum methane production rate was inhibited by 24.5% in CFRs and 48.8% in SBRs due to the existence of tetracycline, while the maximum methane production was reduced by 32.8% in CFRs and 13.8% in SBRs. CFRs exhibited a better recovery capacity during COD shock loading and demonstrated superior propionate degradation and methane production capabilities. Moreover, CFRs achieved better tetracycline removal capacity compared to SBRs. Biodegradation was found to be the dominant tetracycline removal pathway, accounting for 88.9% (CFRs) and 82.0% (SBRs). Long-term exposure to tetracycline decreased archaea abundances and inhibited the enrichment of hydrolytic-acidogenic bacteria (Mesotoga and Syner-01). Meanwhile, CFRs provided a more conducive environment for the enrichment of these microorganisms. The presence of Geobacter in conjunction with the detected ethanol in batch experients of CFRs suggested the potential presence of direct interspecies electron transfer, elucidating the enhanced pollutant removal of CFRs. Additionally, Trichococcus, a genus associated with tetracycline removal, was found to be highly enriched with the long-term dosage of tetracycline.

Multi-omic profiling of a novel activated sludge strain Sphingobacterium sp. WM1 reveals the mechanism of tetracycline biodegradation and its merits of potential application.

As an emerging pollutant, the antibiotic tetracycline (TC) has been consistently detected in wastewater and activated sludge. Biodegradation represents a potentially crucial pathway to dissipate TC contamination. However, few efficient TC-degrading bacteria have been isolated and a comprehensive understanding of the molecular mechanisms underlying TC degradation is still lacking. In this study, a novel TC-degrading bacterium, designated as Sphingobacterium sp. WM1, was successfully isolated from activated sludge. Strain WM1 exhibited a remarkable performance in degrading 50mg/L TC within 1 day under co-metabolic conditions. Genomic analysis of the strain WM1 unveiled the presence of three functional tetX genes. Unraveling the complex molecular mechanisms, transcriptome analysis highlighted the role of upregulated transmembrane transport and accelerated electron transport in facilitating TC degradation. Proteomics confirmed the up-regulation of proteins involved in cellular biosynthesis/metabolism and ribosomal processes. Crucially, the tetX gene-encoding protein showed a significant upregulation, indicating its role in TC degradation. Heterologous expression of the tetX gene resulted in TC dissipation from an initial 51.9mg/L to 4.2mg/L within 24h. The degradation pathway encompassed TC hydroxylation, transforming into TP461 and subsequent metabolites, which effectively depleted TC's inhibitory activity. Notably, the tetX genes in strain WM1 showed limited potential for horizontal gene transfer. Collectively, strain WM1's potent TC degradation capacity signals a promise for enhancing TC clean-up strategies.

Impacts of draw solutes on the fate of tetracycline in an osmotic membrane bioreactor: Role of the combination between membrane fouling and microorganisms

Osmotic membrane bioreactors (OMBRs) are considered a suitable technology for treating wastewater containing tetracycline due to their high rejection and biodegradation efficiency. However, the impact of membrane fouling layer (i.e., chemical composition, microbial composition, and formation) on the filtration and biodegradation of tetracycline is still unclear. Herein, the effects of draw solute concentration and type on the formation of a membrane fouling layer for tetracycline filtration and its relationship with microbial activity were investigated. The results showed that over 99% of tetracycline was retained on the feed side by membrane rejection, and the fouling layer played an important role in tetracycline filtration. Specifically, membrane foulants resulted in a more hydrophilic membrane facilitating tetracycline filtration, while the tetracycline-degrading genera from the fouled membrane promoted tetracycline degradation. The structure equation model showed that tetracycline filtration dominated by electrostatic repulsion between tetracycline and the fouled membrane was more important than tetracycline degradation for tetracycline removal (path coefficient of 0.655 vs. 0.395). This study provided insights into the combined effect of membrane foulants and microorganisms on tetracycline removal.

Removal of tetracycline in nitrification membrane bioreactors with different ammonia loading rates: Performance, metabolic pathway, and key contributors

Membrane bioreactors (MBRs) have been widely applied for the treatment of wastewater that contains high concentrations of both ammonium and antibiotics. Nonetheless, information about tetracycline (TC) removal in nitrification MBRs with high ammonium loading rates (ALRs) is still very limited. Herein, the fate of TC at four different concentrations of 1, 5, 20, and 50 mg/L in three parallel lab-scale nitrification MBRs with different ALRs (named AN50, AN500, and AN1000) were investigated in this study. Excellent nitrification performance and high TC removal efficiency (90.46%) were achieved in AN1000 at influent TC concentration of 50 mg/L. Higher ALRs promoted the removal of TC at lower influent TC concentration (≤5 mg/L), while no significant difference was observed in TC removal efficiencies among different ALRs MBRs at higher influent TC concentration (≥20 mg/L), implying that the heterotrophic degradation could be strengthened after long-term exposure to high concentration of TC. Batch tests demonstrated that adsorption and biodegradation were the primary TC removal routes by nitrification sludge, of which both autotrophic ammonia oxidizers and heterotrophic microorganisms played an important role in the biodegradation of TC. FT-IR spectroscopy confirmed that amide groups on the sludge biomass contributed to the adsorption of TC. Mass balance analyses indicated that biodegradation (63.4–88.6% for AN50, 74.5–88.4% for AN500 and 74.4–91.4% for AN1000) was the major mechanism responsible for the removal of TC in nitrification MBRs, and its contribution increased with influent TC concentration, while only 1.1%–15.0% of TC removal was due to biosorption. TC was progressively degraded to small molecules and the presence of TC had no notable effect on membrane permeability. These jointly confirmed TC could be effectively removed via initial adsorption and subsequent biodegradation, while biodegradation was the primary mechanism in this study.

Metabolomics reveals the mechanism of tetracycline biodegradation by a Sphingobacterium mizutaii S121

Contamination by tetracycline residues has adverse influences on the environment and is considered a pressing issue. Biodegradation is regarded as a promising way to treat tetracycline residues in the environment. Here, strain Sphingobacterium mizutaii S121, which could degrade 20 mg/L tetracycline completely within 5 days, was isolated from contaminated soil. The characteristics of tetracycline degradation by strain S121 were investigated under various culture conditions. Response surface methodology was used to predict the maximum tetracycline degradation ratio, which can be obtained under the following conditions: 31.36 °C, pH of 7.15, and inoculum volume of 5.5% (v/v). Furthermore, extracellular tetracycline biodegradation products and intracellular metabolic pathways of S121 were detected by ultraperformance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) and UHPLC-quadrupole electrospray (QE)-MS, respectively. The results identified eight possible degradation products, and three putative degradation pathways were proposed. In addition, exposure to tetracycline produced significant influences on metabolic pathways such as pyrimidine, purine, taurine and hypotaurine metabolism and lysine degradation. Consequently, the intracellular metabolic pathway response of S121 in the presence of tetracycline was proposed. These findings are presented for the first time, which will facilitate a comprehensive understanding of the mechanism of tetracycline degradation. Moreover, strain S121 can be a promising bacterium for tetracycline bioremediation.

Ag-TiO2/biofilm/nitrate interface enhanced visible light-assisted biodegradation of tetracycline: The key role of nitrate as the electron accepter

Due to the pivotal role of Ag-TiO2/biofilm/nitrate interface, enhanced visible light-assisted biodegradation of tetracycline (TC) in anoxic system was realized through both batch experiment and long-term operation in this study. The results of the batch experiment elucidated that 50 mg L−1 TC could be completely removed within 10 h in Ag-TiO2/biofilm/nitrate system. The continuous flow experiment was operated for 75 d to evaluate the performance and stability of Ag-TiO2/biofilm/nitrate system. TC removal efficiency in Ag-TiO2/biofilm/nitrate system was as high as 92.4 ± 1.6% at influent TC concentration of 50 mg L−1 TC and hydraulic retention time (HRT) of 10 h, which would be attributed to the promoted separation of photoholes and photoelectrons at the presence of nitrate as electron acceptor. Facilitated electron transfer between semiconductor and biofilm was beneficial for enhancing TC biodegradation, thus lowering toxicity of intermediate products and promoting microbial activity. Moreover, the species related to TC biodegradation (Rhodopseudomonas, Phreatobacter and Stenotrophomonas), denitrification (Thauera) and electron transfer (Delftia) were enriched at Ag-TiO2/biofilm/nitrate interface. Besides, a possible mechanism involved in enhanced TC degradation and nitrogen removal at Ag-TiO2/biofilm/nitrate interface was proposed. This study provided a novel and promising strategy to enhance recalcitrant TC removal from industrial wastewater.

Acetate stimulates tetracycline biodegradation pathways in bioelectrochemical system

Tetracycline (TC) is a widely used pharmaceutical and personal care product (PPCP), and considering its biotoxicity in aquatic systems, the metabolism and stimulation of TC in wastewater purification processes are still deserving of concern. This study reveals the stimulation of TC biodegradation by acetate in bioelectrochemical systems (BESs). Attributed to the abundance of exoelectrogens Geobacter (mainly G. sulfurreducens) and putative TC-degraded bacteria (PTDB) in the electroactive biofilm samples, 94% of 100 mg/L TC decomposed within 48 h. Limited acetate (0.1 g/L, AC-0.1) as a cosubstrate enhanced the removal efficiency of TC by 44% when compared to abundant acetate (1 g/L, AC-1) and controls. This resulted from the enhancement of PTDB and the stability of the Geobacter population under limited acetate stimulation. With the differentiation of the microbial community, ubiquinone and other terpenoid-quinone biosynthesis and histidine metabolism were significantly upregulated in AC-0.1 but downregulated in AC-1, another factor that enhanced the removal efficiency of TCs. Here, we concluded that limited acetate could partially relieve the selective pressure of TC and improve the biodegradation of TC, and the catabolism pathways, as well as the main metabolites, were stimulated by acetate and its concentration.

Biodegradation of Tetracycline by Enriched Bacterial Consortia: Microbial Community Succession and Degradation Characteristics and Mechanism

Biodegradation of Tetracycline by Enriched Bacterial Consortia: Microbial Community Succession and Degradation Characteristics and Mechanism

Biodegradation of tetracycline using hybrid material (UCPs-TiO2) coupled with biofilms under visible light

To develop a more green and effective method for tetracycline (TC) removal, a hybrid material (conversion phosphors-TiO2, UCPs-TiO2) was coupled with a biofilm to achieve enhanced removal of TC. The removal of TC by biofilm coupled with UCPs-TiO2 under visible light reached 82%, which was 35% higher than that in treatment using only the biofilm. Extracellular polymeric substance (EPS) promoted the production of hydroxyl radicals by UCPs-TiO2, as the EPS acted as an electron transfer medium and accelerated the TC mineralization. Biofilm in the coupled system tolerated TC stress by regulating its antibiotic resistance genes (ARG) and superoxidedismutase (SOD), and allowed it to maintain stable and efficient removal of TC. This study documents a method to couple a hybrid material with microbial aggregates, creating a promising system for removing refractory organics, such as TC, from water. The study also offers insight into the mechanisms underlying TC removal by microbial aggregates combined with new functional materials.

The performance of aerobic granular sludge for simulated swine wastewater treatment and the removal mechanism of tetracycline

In this study, aerobic granular sludge (AGS) cultivated in a sequencing batch reactor (SBR) was employed to investigate its ability on the decontamination of tetracycline (TC) from swine wastewater (SWW). The removal mechanism of TC by AGS was studied. Results showed that the AGS process could effectively remove chemical oxygen demand (COD), ammonium nitrogen (NH+ 4-N), total phosphorus (TP), and TC during operation. The removal of TC by AGS was mainly due to adsorption and biodegradation, and the contribution rate of biodegradation increased after AGS adaptation to TC. Twenty-two by-products were detected during biodegradation of TC, and accordingly the degradation pathway of TC was speculated. Compared to the control reactor, the microbe diversity in different levels of classification was richer in the TC fed reactor according to the LefSe analysis. The results revealed that enzymes that participated in the metabolic pathway of microbial biodegradation of polycyclic aromatic compounds were enriched and may have played a key role in the biodegradation of TC.

Biodegradation of Tetracycline Antibiotic by Laccase Biocatalyst Immobilized on Chitosan-Tripolyphosphate Beads

In this study, biodegradation of tetracycline, which is one of the most commonly used antibiotics, was investigated. In order to convert tetracycline into inactive oxidative metabolites, laccase immobilized onto rigid tripolyphosphate-treated chitosan beads was utilized. For immobilization, chitosan surfaces were activated with glutaraldehyde-linker reagents after tripolyphosphate treatment. The glutaraldehyde-linked rigid chitosan beads showed the higher immobilization capacity of laccase, providing thermostability, reusability, and the higher tetracycline transformation activity. Subsequently, synthetic mediators, including 2,2'‑azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and lignophenolic mediators like violuric, syringic and ferulic acids, 1-hydroxybenzotriazole, and vanillin, were investigated to activate laccase as electron mediators with KI assistance. Among them, the immobilized laccase showed highest tetracycline antibiotic inactivation activity when ABTS was used as a mediator. In the presence of KI, violuric and ferulic acids, 1-hydroxybenzotriazole and vanillin functioned as laccase mediators and inactivated tetracycline almost completely, however, the effect was not observed when they did individually. Finally, Vmax of the immobilized laccase was determined as 76.3 ± 4.3 µmoles mg–1 min–1 against tetracycline, which was 2-fold higher than that of the free enzyme. These results will provide novel insights into laccase-based removal of non-biodegradable organic matter.

Optimization of media composition for enhancing tetracycline degradation by Trichosporon mycotoxinivorans XPY-10 using response surface methodology

ABSTRACT The objective of the study was to improve tetracycline degradation efficiency by Trichosporon mycotoxinivorans XPY-10 using statistical experimental designs. Different culture conditions (FeSO4, pH and glucose) were optimized for tetracycline biodegradation and the mutual interactions between these three variables were analysed using Box–Behnken design (BBD) and response surface methodology (RSM). The results showed that the empirical model was suitable for experimental data, and the maximum tetracycline degradation efficiency by XPY-10 was 95.18% under the optimum conditions of 0.02% of FeSO4, pH 7.83 and 0.28% of glucose, which was further verified by experiments. This study indicated the excellent ability of XPY-10 in degrading tetracycline and theoretical support for the follow-up practice to remediate tetracycline contaminated environment.

Removal process of antibiotics during anaerobic treatment of swine wastewater

High concentrations of antibiotics in swine wastewater pose potentially serious risks to the environment, human and animal health. Identifying the mechanism for removing antibiotics during the anaerobic treatment of swine wastewater is essential for reducing the serious damage they do to the environment. In this study, batch experiments were conducted to investigate the biosorption and biodegradation of tetracycline and sulfonamide antibiotics (TCs and SMs) in anaerobic processes. Results indicated that the removal of TCs in the anaerobic reactor contributed to biosorption, while biodegradation was responsible for the SMs’ removal. The adsorption of TCs fitted well with the pseudo-second kinetic mode and the Freundlich isotherm, which suggested a heterogeneous chemisorption process. Cometabolism was the main mechanism for the biodegradation of SMs and the process fitted well with the first-order kinetic model. Microbial activity in the anaerobic sludge might be curtailed due to the presence of high concentrations of SMs.

Effects of carbon source, nitrogen source, and natural algal powder-derived carbon source on biodegradation of tetracycline (TEC)

The present study aimed to investigate Klebsiella sp. SQY5-mediated tetracycline (TEC) degradation, nitrogen (N) conversion, and mechanisms underlying this process as influenced by various carbon and N sources under aerobic conditions. Effects of additional organic carbon sources on TEC degradation and N conversion processes were explored, and we found that 34.71% of TEC was degraded at removal rates of 0.97 mg·L−1·h−1 for NH4+-N and 1.97 mg·L−1·h−1 for NO3−-N. A study examining powder natural algal powder in aquaculture wastewater as a carbon source for TEC degradation and denitrification process was also discussed. It suggested that 49.95% of TEC and 60.45% of NO3−-N were removed with a reduction and denitrification rate of 0.11 mg·L−1·h−1 and 1.34 mg·L−1·h−1, respectively, within 72–108 h. Mechanisms underlying TEC degradation and N conversion processes were also proposed, and analysis indicated that specific functional genes played an important role in this process.

Whole Genome Sequencing and Comparative Genomics Analyses of Pandoraea sp. XY-2, a New Species Capable of Biodegrade Tetracycline.

Few bacteria are resistant to tetracycline and can even biodegrade tetracycline in the environment. In this study, we isolated a bacterium Pandoraea sp. XY-2, which could biodegrade 74% tetracycline at pH 7.0 and 30°C within 6 days. Thereafter, we determined the whole genome sequence of Pandoraea sp. XY-2 genome is a single circular chromosome of 5.06 Mb in size. Genomic annotation showed that two AA6 family members-encoding genes and nine glutathione S-transferase (GSTs)-encoding genes could be relevant to tetracycline biodegradation. In addition, the average nucleotide identities (ANI) analysis between the genomes of Pandoraea sp. XY-2 and other Pandoraea spp. revealed that Pandoraea sp. XY-2 belongs to a new species. Moreover, comparative genome analysis of 36 Pandoraea strains identified the pan and specific genes, numerous single nucleotide polymorphisms (SNPs), insertions, and deletion variations (InDels) and different syntenial relationships in the genome of Pandoraea sp. XY-2. Finally, the evolution and the origin analysis of genes related to tetracycline resistance revealed that the six tetA(48) genes and two specificgenes tetG and tetR in Pandoraea sp. XY-2 were acquired by horizontal gene transfer (HGT) events from sources related to Paraburkholderia, Burkholderia, Caballeronia, Salmonella, Vibrio, Proteobacteria, Pseudomonas, Acinetobacter, Flavimaricola, and some unidentified sources. As a new species, Pandoraea sp. XY-2 will be an excellent resource for the bioremediation of tetracycline-contaminated environment.

Simultaneous degradation of tetracycline and denitrification by a novel bacterium, Klebsiella sp. SQY5

Polluted waters with a high residue of tetracycline also have a high concentration of nitrate. Thus, screening for both, highly efficient tetracycline biodegradation and nitrate transformation, is a key technical strategy. In this study, a novel tetracycline degrading strain, SQY5, which was identified as Klebsiella sp., was isolated from municipal sludge. Biodegradation characteristics of tetracycline were studied under various environmental conditions; including inoculation dose (v/v), initial tetracycline concentration, temperature, and pH. Response surface methodology (RSM) analysis demonstrated that the maximum degradation ratio of tetracycline can be obtained under the condition with an initial tetracycline concentration of 61.27 mg L−1, temperature of 34.96 °C, pH of 7.17, and inoculation dose of 29.89%. Furthermore, this was the first report on the relationship between the degradation of tetracycline and the denitrification effect, showing that a maximum tetracycline reduction rate of 0.113 mg L−1·h−1 and denitrification rate of 4.64 mg L−1·h−1 were observed within 32 h and 92 h of SQY5 inoculation, respectively. The data of this study has the potential for use in engineering processes designed for the simultaneous biological removal of nitrates while degrading antibiotics.

Removal of tetracycline by aerobic granular sludge and its bacterial community dynamics in SBR.

In this study, the removal efficiency and mechanism of tetracycline by aerobic granular sludge (AGS) in SBR were investigated. The removal of tetracycline present in livestock and poultry wastewater and the effect on conventional pollutants, such chemical oxygen demand, and nitrogen and phosphorous removal performance have been assessed demonstrating that AGS was able to remove tetracycline by adsorption and biodegradation processes. The removal rate of tetracycline was more than 90%, and conventional pollutants were also efficiently removed. The high-throughput sequencing technology was applied to decipher the species succession and community structure of tetracycline-resistance granular sludge. The Chryseobacterium, Actinotignum, Lactococcus, Shinella and Clavibacter were gradually dominant and considered as the functional bacteria for the removal of tetracycline. The numbers of functional genes including amino acid, carbohydrate and inorganic ion transport and metabolism, as well as energy production and conversion, and secondary metabolites biosynthesis, were also increased. These functional genes played an important role in the biodegradation of tetracycline.

Biodegradation of tetracycline by the yeast strain Trichosporon mycotoxinivorans XPY-10

ABSTRACTWe investigated the behavior of tetracycline degradation and its degradation products upon treatment of isolated yeast that we termed “XPY-10.” XPY-10 was isolated from wastewater and identified as Trichosporon mycotoxinivorans by morphological and physiological tests and 5.8S rRNA ITS sequencing. In our experiments, 78.28 ± 0.8% of tetracycline was removed within 7 days with XPY-10. The degradation of tetracycline fitted well with the first-order kinetic model. We also speculated upon the biodegradation products formed during biodegradation. The possible structures of five products were determined using liquid chromatography–tandem mass spectrometry. During practical application, XPY-10 was shown to have an obvious influence on biodegradation, and 89.61% of tetracycline was removed in feedlot sewage after 7 days of reaction. The chemical oxygen demand removal reached 73.47%.